Disk brakes for automobiles have proven highly popular and a number of these disk brakes do include some sort of internal air cooling in an effort to remove heat from the braking system. With any friction brake arrangement, there is a build-up of heat and the brake must dissipate this energy to the surrounding environment. This problem becomes more acute in race car applications or higher load applications such as trucks or trains in that there is less opportunity to dissipate this energy to the surrounding environment between braking applications.
To overcome a number of these problems, there are various high temperature materials which are used for the brake pads and the actual braking surfaces can also be of a high temperature material. Unfortunately, some of these materials are susceptible to damage such as warping which can easily occur if sufficient water strikes these surfaces when they are hot. There is a real problem associated with brakes which do not effectively transfer energy to the environment at a sufficiently high rate. A low rate of heat transfer leads to high brake temperatures which can substantially reduce performance, typically referred to as brake fade or, in more extreme cases, brake failure. The problems are not limited to merely the braking surfaces per se, as the energy does travel through surrounding components and can reach the wheel bearings causing other temperature problems such as melting of the grease and/or premature failure of bearings. Most bearings have an upper temperature range much lower than the temperatures for race car brakes. Furthermore, the hydraulic fluid used to actuate the brake pads and various hydraulic components thereof also have a maximum temperature limit much less than the maximum temperature of the braking surfaces.
Drum type brakes do not generate as much heat as disk brakes, however, they are generally not being as efficient as disk brakes. Furthermore a number of arrangements have been proposed which use a ring brake having pads at either sides of the ring braking member. Such ring brakes have the capability of providing a large braking surface at a substantial distance from the axis of rotation whereby a large braking force can be generated. This implies that a high heat load will be generated under high brake load conditions. Problems occur in trying to dissipate this heat load, particularly under repetitive braking applications.
The present invention seeks to provide a ring brake system which effectively dissipates heat from the ring braking member, the ring brake pads and the brake caliper arrangement.